Motorists in the UK are wasting £246 million a year on fuel and putting lives at risk by driving on dangerously underinflated tyres, according to Michelin. The tyre manufacturer analysed results from more than 23,000 cars in the UK and found that 37 per cent had at least one tyre classed as either “dangerously underinflated” or “very dangerously” underinflated.

In all, 62 per cent of vehicles were found to have underinflated tyres, while five per cent of vehicles had a tyre with a puncture and one per cent had tread depths below the legal minimum of 1.6mm.

The figures come from eight years of Michelin-run events and they suggest attitudes to tyre safety are not improving.

Jamie McWhir, car, van and 4×4 technical manager for Michelin in the UK, said: “The proportion of cars with dangerously underinflated tyres has pretty much stayed the same over the eight years we have been running our Fill Up With Air events.

“That’s pretty depressing when you consider the volume of vehicles and the implications. Seriously underinflated tyres are dangerous, they use more fuel, they wear out quicker and they cause the car to produce more pollutants and greenhouse gases.”

Michelin classifies tyres that are between 7psi and 14psi below the manufacturer’s recommendation as “dangerously underinflated”, while 14 psi or more underinflation is deemed to be “very dangerous.”

Running a car with tyres underinflated by 7psi decreases fuel efficiency by about one mile per gallon. If average fuel consumption is assumed to be 45 miles per gallon on correctly inflated tyres, and average distance driven is 7,900 miles a year, motorists on 7psi underinflated tyres are using on average 18.2 litres of fuel a year unnecessarily.

At an average fuel cost across diesel and unleaded of £1.18 per litre, that means 11.84 million of the UK’s 32 million cars are wasting a total of more than £254 million a year.

In addition, more than 538,000 tonnes of excess CO2 are being emitted by those cars.

Mr McWhir added: “It’s crucial that motorists understand the importance of driving on tyres with the correct pressure, especially as they’re the only point of contact with the road and are therefore critical to the safety of the vehicle, its passengers, other road users and pedestrians.

“Last year the Department for Transport found that dangerous tyres were responsible for more than 40 per cent of vehicle defect related deaths. It is so important to fit tyres of a sufficient quality and then look after them properly.”

Michelin recommends checking tyre pressures – including the spare tyre – at least every month and before every long journey.

Last month industry campaign group TyreSafe and Highways England found that more than 10 million tyres in use on roads in England, Scotland and Wales could be illegal.

Stuart Jackson, TyreSafe chairman, said: “It’s a question of educating motorists to take responsibility for their safety and that of others on the road.

“As vehicles have become increasingly reliable, owners have become less used to performing what were once considered basic precautionary checks before setting off on a journey. Tyres too are much more technologically advanced but they do wear and can get damaged so it is down to the driver to regularly check they’re safe

“Awareness among Britain’s motorists of the importance of tyre safety urgently needs to improve.”

Michelin inspected 23,741 cars over the past eight years as part of its Fill Up With Air roadshow which tours the UK offering free pressure and tyre checks for motorists, as well as tyre maintenance and road safety advice.

Top tips from Michelin for looking after your tyres and staying safe on the road:

1. Check your tyre pressure every month and before a long journey. Driving a car with the correct tyre pressure increases safety and saves fuel.

The recommended tyre pressure levels for front and rear tyres are often different so refer to the vehicle handbook to get these right. Pressures could also be listed on the ledge inside the driver’s door or inside the fuel cap.

Don’t forget to check the pressure of the spare tyre if there is one.

Buy a pressure gauge so you can take accurate readings.

2. Regularly check the tread depth of your tyres and replace them when they are worn.

Change your tyres before the tread depth is worn to the legal minimum of 1.6mm. The more tread you have on your tyres, the more water they can disperse.

A simple way of checking the tread is to perform the ‘20p test’

Take a 20p piece and place it between the main grooves of the tyre

If the outer strip of the coin can be seen then it’s likely your tyre doesn’t have the legal minimum tread depth.

Perform the test on at least three locations on each tyre.

Drivers whose tyres fail to comply with the minimum tread depth risk a fine of up to £2,500 and three penalty points for each illegal tyre.

3. Inspect the appearance and condition of your tyres on a regular basis for cracks, lumps, bumps, tears and bulges as this could show damage. If you spot any of these, make sure you get them checked by a qualified tyre expert so that it can be repaired or replaced where appropriate.

British motorists are collectively wasting more than £1 billion a year despite petrol prices breaking through the £5 a gallon mark and diesel hitting £1.29 a litre, by failing to keep an eye on their tyre pressure.

Research by Cooper Tire Europe found that, at any one time, a staggering 95 percent of vehicles on the road have at least one tyre under inflated by 10 percent. This not only increases fuel consumption and reduces the life of the tyre, but also increases the risk of accidents.

Under inflated tyres are harder to get moving, and can result in an increase of 2.5 percent in fuel consumption – an unwanted extra expense considering UK motorists spent £34 billion on fuel last year.

With around 30 million passenger vehicles on the roads, and an average cost of 14.74 pence per mile for petrol cars and 12.81 pence per mile for diesel cars, drivers of affected vehicles are unwittingly shelling out an extra £44.22 per year each (£38.43 for diesel drivers) – a collective total of £1.26 billion*.

Alarmingly, under inflated tyres also increase stopping distances and are therefore a contributory factor to road accidents. Department for Transport data reveals that defective and under inflated tyres cause 1,000 serious injuries or fatalities every year.

“Checking your tyre pressures is a mundane, but very simple, task,” says Cooper Tire product manager, Malcolm Jones. “As the ‘credit crunch’ grips the country, it’s amazing that drivers aren’t bothering to do it, as it could save them money and, more importantly, keep them safe on the road.”

Cooper Tire recommends that motorists check their tyre pressures at least once a month, or whenever they fill up at a petrol station.